Electro-thermal actuator switches have been known heretofore. They have been commonly of the circuit breaker type wherein the contacts are manually closed and latched and the latch is tripped to open the contacts in response to an abnormal current flowing in the circuit closed by such contacts to protect a branch circuit or the like from excessive currents. However, such breakers are normally manually actuated only from off to on and are not normally adapted to serve as switches for closing and opening a load circuit but rather as protective devices on over-current.
Electro-thermal delayed action switches have also been known wherein a delayed-action thermal circuit is closed locally simultaneously with actuation of the switch to closed position, and after a time interval the thermal element trips a latch to release the switch to open position.
Thermal relays have also been known wherein separate heaters controlled by a pair of auxiliary contacts control a bimetal to close and open a switch.
While these prior devices have been useful for their intended purposes, this invention relates to improvements thereover.